During the drilling, stimulation, completion, and production phases of wells for petroleum or water extraction, the downhole use of compositions having high viscosities is important for a wide variety of purposes. Higher viscosity fluids can more effectively carry materials to a desired location downhole, such as proppants. Similarly, higher viscosity drilling fluids can more effectively carry materials away from a drilling location downhole. The use of higher viscosity fluids during hydraulic fracturing generally results in larger more dominant fractures.
One common way to attain high viscosities in drilling fluids is to use a mixture of water and a viscosifier, such as guar gum. However, typically viscosifiers must be added in high concentrations to provide viscosities sufficient to suspend a desired proppant, which can result in high transportation costs and low efficiency preparation of viscous materials. Viscosifiers are frequently prone to uneven wetting, forming lumps or “fish eyes” during mixing with liquids, which can damage subterranean formations and can require longer mixing times or more sophisticated mixing equipment. Viscosifiers generally unevenly viscosify liquids of different polarities, forming mixtures with inhomogenous and relative unpredictable or variable properties in solutions with multiple liquids.
In addition, the presence of certain ions in water can limit, reduce, or degrade the viscosity of certain viscosifiers. This limits the use of certain ion-containing water, such as sea water, or water recovered from or naturally produced by some subterranean formations. As a result, the oil and gas industry spends substantial amounts of money and energy to obtain fresh water used for drilling fluid applications, such as for fracturing fluid, or avoids formations having substantial concentrations of particular ions, shrinking the value and size of the market and reducing the number of customers to whom fracturing services can be provided.